The present invention relates to the field of data processing systems, and more particularly to the location of devices within such systems.
Many current mid to high-end computer systems (e.g., network servers) include mass storage devices (hard files) configured as an array, and one common configuration places the computer system and array in a loop enabling bi-directional data transfer between the two.
With reference to FIG. 1, each hard file 10 is typically held in a carrier device 20 for insertion into the computer housing (not shown) using rails 30 on the carrier 20. The carrier device also has a latch 40 such that it can be locked into place within the computer housing.
FIG. 2a shows the inside of a computer housing 60 which is specially adapted to receive the carrier device shown in FIG. 1. The rails 20 of the carrier device engage with a set of rails 70 inside the computer housing and enable the carrier to be slid into place. FIG. 2b shows an enlarged view of the inside of computer housing 60 and FIG. 3 shows hard file 10 in its carrier 20 being inserted into place within computer housing 60.
At the end of the rails 70 inside the computer housing sits a backplane which spans the length of the computer system box. FIG. 4 shows a backplane 80 of the prior art which includes a plurality of female connectors 90 and some logical circuitry 95 for carrying out computing function. On the back of the hard file is a male connector (not shown). The carrier device containing the hard file is slid down the computer system""s rails towards the backplane until the male connector engages with the appropriate female connector on the backplane. This connection usually takes the form of one of the industry-standard protocols such as SCSI (Small Computer Systems Interface) or SSA (Serial Storage Architecture).
The docking of the hard file with the backplane is a very precise art. The backplane is fixed, whilst the hard file has limited movement within the carrier device. The misalignment of the hard file connector with the backplane connector can frequently be up to 0.7 mm and when such a misalignment occurs, it is necessary to force the hard file connector into the correct position before docking can take place. The carrier is locked into position using latch 40 and this latch aids in forcing the two connectors to engage.
The backplane is an expensive piece of equipment. During the forced docking of a hard file thereon, it is highly likely that the backplane may be over stressed by such forcing, resulting in the failure of one or more of its connectors or circuitry (components). Failure of even a single backplane connector requires the computer system to be shut down in order for the entire backplane to be replaced. This is highly inconvenient for customers who typically expect high data availability.
Further whilst the carrier device is locked in place, the hard file connector is prone to some degree of movement. The environment in which the computer system is place may be the cause of this (e.g., outside resonance). This too can lead to the backplane becoming stressed and damaged, requiring complete replacement thereof.
Accordingly, the invention provides an enclosure comprising: a housing; and a device connecting card compliantly connected within the housing, whereby in use the compliant connection disperses mounting stresses caused by a device in the housing.
According to a preferred embodiment, the connection is laterally compliant.
In a preferred embodiment, the compliant connection comprises an electrical connection. In the prior art the electrical connection typically is a male/female connection which can easily become stressed due to movement of the connecting device during operation thereof (this may be caused by the environment in which the enclosure is placed (e.g. outside resonance). Use of a compliant connector means that such stress does not occur.
Preferably the compliant connection is resilient in order to provide an dampening effect (e.g., on operational vibrations of a hard file.)
In one embodiment, the electrical connection comprises a backplane, pressure connector means provided on a first face of the card and contacts provided on the face of the backplane which is opposite the first face of said card. It is the pressure connector means being in contact with the contacts on the backplane which form the electrical connection between the card and the backplane. The use of pressure connectors is also particularly advantageous because there are no connector pins which could become damaged by, for e.g., outside resonance/vibrations (e.g. such vibrations may cause the device connected to the card to move and this could have previously resulted in damage to the connector pins). Further the compliant connector is tolerant of movement of the card with respect to the backplane and does not break electrical contact with the contacts on the backplane when such movement occurs.
Preferably the contacts are conductive pads. These may, for example, be made of gold plated copper. The pads should be chosen such that they do not easily rust.
Preferably the card is dimensioned to provide a greater surface area than the backplane. This means it is possible to provide a greater degree of functionality on the card than would previously have fitted onto the backplane. For example, extra memory could be added.
In a preferred embodiment, the compliant connection comprises a mechanical connection. The lateral movement preferably permitted by the mechanical connection allows, for example, a connector on the card to align itself with a connector on the back of a device due to engage therewith. It is no longer necessary to force, for example, a hard file connector to dock with the connector on the card. Thus greater assembly tolerances are permitted with regard to the construction of the hard file, its carrier, and the rails by which the carrier engages with the data processing system. A greater degree of misalignment between the hard file connector and the connector on the card is therefore permitted.
In one embodiment the mechanical connection comprises a stud, an aperture in the backplane for receipt of the stud and means for attaching the stud to the backplane. It is a clearance formed between the stud and the card""s aperture which permits laterally compliant movement of the card with respect to the backplane.
The mechanical connection means preferably comprises means for maintaining the card at a controlled distance from the backplane (e.g. the stud). This distance enables an improved flow of across any components on the card to be provided for, enabling improved cooling of such components. The mechanical connection preferably also comprises locking means.
It will be appreciated that the invention is not limited to the use of a stud based mechanical connection. In one embodiment the mechanical connection comprises laterally compliant pillars which could be soldered to the first face of the card and also to the backplane.
Preferably the card has at least one of electrical conversion means and protocol conversion means. For example, the electrical conversion means can make the conversion between single-ended and differential current or between two different voltages. The protocol conversion means could make the conversion between a SCSI hard file and an SSA data processing system.
In a preferred embodiment, the card comprises circuitry for performing computing functions. Of course such circuitry could instead be located on the backplane. However the soldering of components onto the backplane causes it to undergo many temperature changes. Such changes may result in damage occurring to other components on the backplane. By soldering the components onto the card, there is less scope for damage. In any case, the card can be replaced instead of the entire backplane.
Preferably a connector is located on the second face of the card in order for a connector on a device such as a hard file to be able to engage therewith. As previously mentioned, during engagement such a device with a connector on the backplane it was latterly highly likely that the connector/other components thereon would be over stressed and fail. The connector on the backplane/other components could also become stressed due to outside resonance/vibrations etc. Such a failure resulted in the need to replace the entire backplanexe2x80x94a very expensive piece of equipment. Moving the connector onto the card permits replacement of this card rather than the entire backplane. This is therefore extremely advantageous. Likewise, by moving other components previously on the backplane onto the card, only the card should have to be replaced if any of those components fail.
According to another aspect, the invention provides a device connecting card having a compliant connection for mounting the card within an enclosure, whereby in use the compliant connection disperses mounting stresses caused by a device in the enclosure.